<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
      

    </style>
</head>

<body>
    <div id="app">
        <input type="text" :value="str" @input="changeStr">
    </div>
    <script src="./js/vue.js"></script>

    <script>
        let vm = new Vue({
            el: "#app",
            data: {
               str:"王一星"
            },
            methods: {
                changeStr(e){
                    this.str = e.target.value;
                }
            }
        })

    </script>
</body>

</html>